/*!
 * navscroll.js
 * version: 1.2.0
 * author: jeroen hammann
 *
 * copyright (c) 2014 jeroen hammann
 * released under the mit license
*/

;(function ($, window, document, undefined) {
  'use strict';

  var pluginname = 'navscroll',
      defaults = {
        // the time it takes to scroll to the element (set this to 0 so it obviously won't show an animation).
        scrolltime: 500,
        // the class of the items which invokes the scroll animation. all anchor tags inside the element are clickable when the value is empty.
        navitemclassname: '',
        // set the height of the navigation (to use as offset). 'auto' let's the plugin determine the height automatically, a number determines the height in px.
        navheight: 'auto',
        // if your navigation hides and is used as a dropdown on small screens setting this to true hides the dropdown after a click.
        mobiledropdown: false,
        // additionaly you can insert the mobile nav's classname here, when left empty the plugin searches for a <ul> in the same parent element.
        mobiledropdownclassname: '',
        // the window width, which functions as a breakpoint between desktop and mobile.
        mobilebreakpoint: 1024,
        // set to 'true' if you want to enable scrollspy.
        scrollspy: false
      };

  function navscroll(element, options) {
    this.element = element;
    this.options = $.extend({}, defaults, options);

    this._defaults = defaults;
    this._name = pluginname;

    this.init();
  }

  navscroll.prototype = {
    init: function() {
      var self, options, element, navitem, navoffset, scrolltime;
      self = this;
      options = self.options;
      element = self.element;

      if (options.navitemclassname === '') {
        navitem = $(element).find('a');
      } else {
        navitem = $(element).find('.' + options.navitemclassname);
      }

      if (options.navheight === 'auto') {
        navoffset = $(element).height();
      } else if (isnan(options.navheight)) {
        throw new error ('\'navheight\' only accepts \'auto\' or a number as value.');
      } else {
        navoffset = options.navheight;
      }

      navitem.on('click', function(e){
        var url, parts, target, targetoffset, targettop;

        url = this.href;
        parts = url.split('#');
        target = parts[1];

        if (target !== undefined) {
          e.preventdefault();
          targetoffset = $('#' + target).offset();
          targettop = targetoffset.top;
        }

        if ($(this).data('scrolltime') !== undefined) {
          scrolltime = $(this).data('scrolltime');
        } else {
          scrolltime = options.scrolltime;
        }

        if (options.mobiledropdown && $(window).width() >= 0 && $(window).width() <= options.mobilebreakpoint) {
          if (options.mobiledropdownclassname === '') {
            $(element).find('ul').slideup('fast');
          } else {
            $('.' + options.mobiledropdownclassname).slideup('fast');
          }
        }

        $('html, body').stop().animate({
          scrolltop: targettop - navoffset
        }, scrolltime);
      });

      if (options.scrollspy) {
        var scrollitems;
        scrollitems = [];

        navitem.each(function() {
          var scrollitemid = $(this).attr('href');
          scrollitems.push($(scrollitemid));
        });

        $(window).on('scroll', function () {
          self.scrollspy(navitem, scrollitems);
        });
        self.scrollspy(navitem, scrollitems);
      }
    },

    scrollspy: function(navitem, scrollitems) {
      var scrollpos, changebounds, i, l;
      scrollpos = (document.documentelement && document.documentelement.scrolltop) || document.body.scrolltop;
//  changebounds = window.innerheight / 2 || document.documentelement.clientheight / 2;
      l = navitem.length;

      for (i = 0; l > i; i++) {
        var item = scrollitems[i];
        if (scrollpos > item.offset().top - 43) {
          navitem.removeclass('active');
          $(navitem[i]).addclass('active');
        }
      }
    }
  };

  $.fn[pluginname] = function (options) {
    return this.each(function () {
      if (!$.data(this, 'plugin_' + pluginname)) {
        $.data(this, 'plugin_' + pluginname,
        new navscroll(this, options));
      }
    });
  };

})(jquery, window, document);